XO help for AE TD12m & SEOS12 MTM - AVS Forum
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Old 11-24-2013, 01:29 PM - Thread Starter
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I'd like to build an MTM using two of the AE Lambada 12 and the SEOS 12 with the DNA360 or Radian 475. Problem is that I know nothing about passive xo design, only how to build them from plans. I'm hoping somebody already has something put together or is willing to put some thought in to the design. There has been quite a bit of talk, but nothing has been executed with the design for the 12" mtm aside from the active kits that AE might be putting together with the MiniDSP Ice plate amps and Radian 475. They will be a killer kit, but I want passive. Perfect world for me on this would be Bwalso's design of the td12m and dna360/SEOS12 - plus a td12x in a larger enclosure tuned to the low 30's. I would use the Radian 475 if it's worth the extra $100, and I could just buy all the drivers from AE.

Any takers?
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Old 11-25-2013, 04:33 AM
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I am curious as to how that Radian 475 compared to the DNA-360, as the Radian cost a good bit more. I know that Radian makes excellent CD's, and I actually own a Radian 951PB, but I have my doubts that the 475 is that much better than the DNA-360, although I could be wrong.

I would much rather see this build with the Seos-15's rather than the 12's, but am looking forward to your progress none the less!
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Old 11-25-2013, 07:15 AM - Thread Starter
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I am for the DIY camp of "more for less" so if the two CDs are pretty close, I would prefer the Denovo. The Radian goes up to 21k hz and has an aluminum diaphragm. The Denovo Has a polyamide diaphragm and goes up to 18k hz. I just have the building skills so I'm at a loss to know which would sound better and why, or how to design it. I know the sound I'm looking for though. Robotbunny's SEOS w/ td12m sound incredible to me, so I'm sure the dna360 is good enough for me. I need them to dig deeper to blend better with G-horns.

The 15 would be nice, but space restraint keeps me at the 12" for the drivers and waveguide. The 15s wouldn't be that much more money.
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Old 11-25-2013, 07:02 PM - Thread Starter
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John at AE gave me some advise today to scratch the mixed up driver idea and stick with two TD12m instead, with a tuning of 45hz in 4 cubes. He mentioned that the 12x and 12m could be used together, but the 12x would have to be active and the 12m would need to be crossed around 180hz.

What kind of changes would need to be made to Bwaslo's XO to add the 2nd td12m for this?
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Old 11-25-2013, 08:40 PM
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Why the extra complexity, cost, and size of an MTM?

One 12" woofer is enough to make your ears bleed, assuming home use.

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Old 11-26-2013, 06:22 AM - Thread Starter
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The size actually works out better to get it up to the right height. This my poor-man's Neosis minus the $700 coax. I need these to have more of a presence at 60hz for my pair of Gjallarhorns. I'll post up a graph AE sent me showing the estimated capability at 120db running on the power from my Onkyo 818. I will give them a larger amp someday not soon.
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Old 11-28-2013, 08:30 AM - Thread Starter
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Old 11-28-2013, 09:35 AM
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Going from a standard 2way to an MTM is going to require a completely different Xover. The pair of woofers in the MTM alignment have much different polar response than the single. There will be more efficiency from the woofers so less padding is needed on the compression driver. The impedance curve of the pair of woofers is going to be different than that of the single driver also. It isn't a simple matter of changing a couple components. Measuring everything in the cabinet, doing a new simulation, and testing to verify is the only way to really get good results.

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Old 11-28-2013, 10:36 AM - Thread Starter
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I just sent you an email while you were answering most of the questions right here - I appreciate your help, John. I would like to learn xo design, but I'm not sure where to even start, and quite sure this is the wrong project to begin due to the complexity and cost. I still hope I can get somebody with the xo design skills in on this project and make another awesome speaker design for DIYers to choose from.
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Old 11-28-2013, 12:34 PM
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Well, you could take Bill's measurements, plop them into a simulation software and come up with a XO, but it won't be as good as it could be, as John said.
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Old 11-28-2013, 01:26 PM
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IMO best bet for adding another woofer to the existing design without redoing everything from scratch would be to go TMM, using the crossover as designed, sealed cab for the TD12M, and driving the TD12X bass bin with a plate amp. Just be sure to get an amp with continuously adjustable phase and crossover point and you should be able to dial it in to your liking. So, yeah, not a MTM and only mostly passive, but depending on your goals that might be the way to go if you don't find someone willing to design a whole new speaker for you.
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Old 11-28-2013, 04:58 PM - Thread Starter
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John J sent me these pics: first one is the response of two TD12m in 4 cubes, tuned to 45hz. They would work really well with my Gjallarhorns crossed at 60hz, which is why I'm trying to come up with a solution for the MTM. I'm on to scouring the internet for XO design cookbooks.

edit: found it! http://www.diyaudio.com/forums/multi-way/189847-introduction-designing-crossovers-without-measurement.html





This next one combines the original TM as designed by Bill and a separate cab for the 12x or 12h on the bottom. I would use the other 2 channels on my 2x4 miniDSP and a spare EP4000. I like this idea as it would certainly be the easiest route as John, Antisuck, and I all agree. I could run this until I figure out how to make the mtm XO work with the dual 12m. But, I would end up with two drivers I don't need and have to buy two more that I do need. I wish I had a money tree.

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Old 11-29-2013, 11:15 AM
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One of the things to look at is that a lot more power can be applied to the 2way on the top there. If you had desire to upgrade, you can put in 500W to the TD12M without exceeding the excursion limits in a design like that. A single TD12M will then be able to get you in the range of 124dB.

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Old 11-30-2013, 03:22 PM
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Quote:
Originally Posted by antisuck View Post

IMO best bet for adding another woofer to the existing design without redoing everything from scratch would be to go TMM, using the crossover as designed, sealed cab for the TD12M, and driving the TD12X bass bin with a plate amp. Just be sure to get an amp with continuously adjustable phase and crossover point and you should be able to dial it in to your liking. So, yeah, not a MTM and only mostly passive, but depending on your goals that might be the way to go if you don't find someone willing to design a whole new speaker for you.
This is exactly what I would recommend.

Mike
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Old 12-06-2013, 09:07 PM - Thread Starter
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Well, my heart is set on the MTM for this and a passive xo, so I'm scrapping the project until I have a proper design. I will mess around with learning how to build a XO with some other drivers I have laying around and see if I can figure something out, and I have been wanting to learn this part of speaker design. It would be a major bummer to spend $2500 on parts and not have it be amazing. Defeat.frown.gif
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Old 12-06-2013, 10:42 PM
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How far back do you sit? A MTM with such large drivers won't sum well up close.

Mike
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Old 12-07-2013, 07:53 AM - Thread Starter
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